Mavs GM explains how Luka Doncic embarrassed ex-Boston Celtics role player before he was traded

As Dallas Mavericks assistant general manager Michael Finley explained it on 105.3 The Fan in Dallas, Luka Doncic embarrassed former Boston Celtics big Grant Williams during a scrimmage when the latter pressed the former and trash-talked to a man everyone else on the team knew better not to.

“I remember, just to share a quick story with you guys,” Finley said (h/t MassLive). “One day in practice, a player on our team, I won’t call his name out — but it’s Grant Williams. He decided he wanted to get under Luka’s skin. He felt Luka didn’t come that day ready to practice. To make a long story short, they had a scrimmage going and he was talking trash to Luka up and down the court. So finally, Luka says ‘Okay,” and Luka went on a 26-6 run by himself. You can ask anybody, I’m not exaggerating. He showed everything, the 3s, the postups, the floaters, everything by himself.

“(Luka) didn’t say a word. Everybody on the sidelines, including the coaches said do not poke the bear. That’s what everybody kept saying, do not poke the bear. We had guests in the gym at the time and they were on the sidelines oohing and ahhing. It was unbelievable, I was over there and the kid couldn’t miss. I’m not talking easy shots, he was showing the whole repertoire in this five or six minute span. It was a 26-6 run by himself.”

Grant Williams' fit on Mavs always doubted by Boston Celtics reporter

Williams succeeding on the Mavericks was always something MassLive's Brian Robb was skeptical of.

“Williams wanted a big payday and more minutes, which is exactly what he got from the Mavericks,” Robb prefaced before saying, “He showed off his solid 3-point shooting in the victory as Williams also got the start. It’ll remain to be seen how the Mavericks look like this season with Kyrie Irving and Luka Doncic leading the way, but they at least came away with the season-opening win.”

Perhaps Robb was privy to locker room issues Williams' exuberant personality caused while in Boston. It didn't sink the Cs, and all seemed well with Boston's camaraderie, but it's a stretch to think Williams' character did a 180 when he got to Dallas.